JP3938331B2 - Magnetic bearing generator motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a generator motor having a magnetic bearing function that includes two sets of windings with different numbers of poles in a stator and has a magnetic bearing function that levitates and supports a rotor when current flows through the two sets of windings. The present invention relates to a system suitable for accumulating certain energy and consuming the accumulated energy to operate the generator motor as a generator or motor.
[0002]
[Prior art]
The stator of the generator motor is provided with two sets of windings that differ in number of poles by 2n (where n is an integer), and current flows through the two sets of windings, so that static magnetism is generated between the rotor and the stator. According to the generator motor that generates the force, for example, by providing two sets of windings with the main winding of the stator having two poles and the control winding having four poles, rotation by the alternating current flowing in each winding It is known that a static magnetic force in the radial direction is generated by combining magnetic fields. This static magnetic force in the radial direction can be adjusted in any direction and to any magnitude by adjusting the magnitude and phase of the current in the control winding relative to the current of the generator motor in the main winding. Can do. Therefore, a displacement sensor is arranged around the rotor, the floating position of the rotor is detected, and the magnitude and phase of the control winding current are adjusted so that the rotor is levitated and supported at a predetermined position. Thus, it is possible to position and support the rotor at a predetermined floating position as in a normal magnetic bearing.
[0003]
Such a generator motor may be used as a generator or a motor by gradually consuming the energy from an energy source that stores a certain amount of energy. For example, when operating as a flywheel generator, mechanical kinetic energy is stored in a flywheel that rotates at high speed, and the rotor of the generator is directly connected to the flywheel, thereby making the rotor magnetic. The generated power can be output from the stator of the generator while floating and supporting by the bearing function. By using a magnetic bearing / generator motor for such an application, there is no energy loss due to the bearing, and therefore mechanical kinetic energy can be maintained for a long time.
[0004]
In such a type of flywheel generator, since the rotor rotates at high speed and AC power is output, the frequency of the generated power is generally high. For this reason, this AC generated power is rectified and converted into DC power, and this AC power is formed by an inverter device in accordance with the voltage and frequency of a commercial AC power supply and supplied to the customer.
[0005]
[Problems to be solved by the invention]
However, in the magnetic bearing / generator motor configured as described above, the kinetic energy of the flywheel is gradually reduced by extracting the power generation output. That is, the rotational speed of the flywheel gradually decreases, and accordingly, the rotational speed of the rotor of the generator motor decreases, and the generated output voltage gradually decreases accordingly. However, in the inverter device, in order to obtain an AC output of a required output voltage, the voltage of the DC portion needs to be a certain level or more. Therefore, when an AC output having a desired voltage and frequency is obtained from the output side of the inverter device, the DC voltage obtained by rectifying the generator output needs to be boosted to a required DC voltage of the inverter device by a DC / DC converter or the like. is there. In addition, since the output frequency of the generator decreases with a decrease in the rotational speed of the flywheel, there is a problem that the ripple of the output voltage when this is rectified and converted to direct current increases and the power generation quality is impaired.
[0006]
The present invention has been made in view of the above-described circumstances. When a generator motor having a magnetic bearing function is operated as a generator or a motor while using the energy from an energy source that has stored a certain amount of energy, the stored energy is obtained. An object of the present invention is to provide a magnetic bearing / generator motor capable of obtaining a required output even if the power supply decreases.
[0007]
[Means for Solving the Problems]
Magnetic bearings and generator motor of the present invention, the solid poles in stator is 2n (where n is an integer) with only a different first winding and the second winding, said first winding and the second In the generator and motor for magnetic bearings that supports the rotor to be levitated and supported with respect to the stator by passing a current through the winding, one of the first and second windings is used as a main winding. The other winding is the control winding, connected to the main winding and the inverter device for supplying the generated power to the load side, and the control winding is connected to the control current to the winding. Inverter device to be supplied and switching for switching one of the first winding and the second winding from the main winding to the control winding and the other winding from the control winding to the main winding And a vessel .
[0008]
Here, the two sets of windings are preferably two-pole windings and four-pole windings. The generator motor is preferably operated as a generator, and preferably includes means for switching the first winding and the second winding when the output voltage of the generator drops to a predetermined voltage. At this time, it is preferable that the output voltage of the generator rises to a predetermined magnification.
[0009]
According to the present invention described above, a generator motor having a magnetic bearing function is used as, for example, a flywheel generator, so that the kinetic energy accumulated in the flywheel is reduced, thereby reducing the output voltage of the generator. In addition, the initial output voltage can be obtained by switching two sets of windings, for example, a two-pole winding and a four-pole winding provided in the stator of the generator motor. For example, when a two-pole winding is adopted as the main winding and the energy output accumulated in the flywheel starts and the generator output outputs the required voltage, The rotation speed of the wheel decreases and the generator output voltage also decreases. At this time, by switching the main winding of the generator to the quadrupole winding which is the second winding, the electrical angle of the 4-pole winding is smaller than that of the 2-pole winding, so a high output voltage can be obtained. can get. Thereby, even if the energy consumption of the flywheel progresses and the rotational speed thereof decreases, the original output voltage can be obtained by switching the generator output to the four-pole winding. Therefore, when forming the required AC power from the generator output directly connected to the flywheel via the inverter device, the burden on the DC / DC converter etc. in the inverter device can be reduced, and the energy accumulated in the flywheel Can be used effectively, and contributes to the improvement of power generation quality such as the reduction of ripples.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0011]
FIG. 1 shows a power generation system using a magnetic bearing combined generator motor according to an embodiment of the present invention. In this embodiment, the magnetic bearing / generator motor includes a flywheel and operates as a flywheel generator. That is, the generator motor 11 includes a stator 12 and a rotor 13, and a two-pole winding 14 and a four-pole winding 15 are arranged on the stator. The rotor 13 is an induction type non-polar rotor, and its main shaft is directly connected to the flywheel 16.
[0012]
Although not shown, the generator motor 11 is provided with a displacement sensor for detecting the floating position of the rotor 13, and adjusts the magnitude and phase of the current flowing in the control winding with respect to the current flowing in the main winding. Thus, a static magnetic force in the radial direction is generated, and thereby, the rotor 13 is levitated and supported at a predetermined position in a non-contact manner like the magnetic bearing. In the illustrated example, only one generator motor 11 having a magnetic bearing function is shown, but actually, a plurality of generator motors of the same type are provided, thereby supporting the main shaft directly connected to the flywheel 16 at a plurality of locations. To do.
[0013]
In this generator motor 11, for example, a flywheel 16 having a mass of about 100 kg is rotated at a high speed such as 10,000 rotations per minute, thereby storing mechanical kinetic energy. Then, one of the two-pole winding 14 and the four-pole winding 15 is a main winding, and the other is a control winding, so that the rotor 13 can be lifted and supported as a magnetic bearing while generating power from the main winding. Take out. As described above, the generator motor 11 includes the two-pole winding 14 and the four-pole winding 15, so that one of the windings is a main winding and the other winding is a control winding. Thus, in any case, the pole number difference is 2, which can generate a static magnetic force in the radial direction, and the rotor can be supported by levitation by the magnetic bearing function.
[0014]
This power generation system includes a switch 17 that switches between the two-pole winding 14 and the four-pole winding 15. By this switcher 17, a combination in which the two-pole winding 14 is the main winding and the four-pole winding 15 is the control winding, and the four-pole winding 15 is the main winding and the two-pole winding 14 is the control winding. Switching to a combination of lines is possible. On the main inverter device side 18 of the switching device 17 is an inverter device 19 that once rectifies the AC power formed by the generator motor 11 to convert it into DC power, and further converts it into AC power that matches the commercial power frequency and voltage. It is connected.
[0015]
The inverter device 19 includes a converter unit 19a that rectifies the power generation output of the generator motor 11, a DC unit 19b that includes a capacitor that smoothes the rectified voltage and holds it as DC power, and DC / DC that boosts the DC power. A booster 19c, such as a converter, and an inverter 19d that reversely converts the boosted DC power into AC power having a required frequency and voltage. The generated power converted into the frequency / voltage of a commercial AC power source or the like in this way is supplied from the terminal 20 to the load side.
[0016]
On the other hand, the control inverter device side 21 of the switcher 17 is connected to an inverter device 22 for supplying a control current. The inverter device 22 rectifies AC power such as a commercial AC power source and then controls the generator motor 11. It supplies the required control current to the windings. By this inverter device 22, an alternating current having a pole number different from that of the current flowing in the main winding is supplied to the control winding of the stator 12 by adjusting the phase and the magnitude thereof, so that any direction can be obtained. The formation of the static magnetic force is as described above.
[0017]
The switching operation of the switch 17 is performed according to a command from the control device 23. The control device 23 is connected to each of the inverter devices 19 and 22 to monitor these operation states and output a control command to them. That is, when one of the windings is operated as the main winding, when this output voltage decreases and reaches a predetermined value, a switching signal is output to the switch 17 and the main winding is switched to the other winding. Switch. At this time, the inverter devices 19 and 22 are adjusted so that the main winding current and the control winding current maintain the state before switching.
[0018]
FIG. 2 shows the current distribution in each winding inside the stator. The case shown in FIG. 2 (a), a 2-pole winding 14 is adopted as the main winding, a case of adopting the 4-pole winding 15 and the control winding. By using the two-pole winding 14 as a main winding, the illustrated two-pole magnetic flux is formed, thereby forming a two-pole main rotating magnetic field. On the other hand, a 4-pole control magnetic field is formed by the 4-pole winding 15.
[0019]
The case shown in FIG. 2 (b) employs a 4-pole winding 15 as a primary winding, a case of adopting the 2-pole winding 14 as the control winding. By using the quadrupole winding 15 as the main winding, the illustrated four-pole magnetic flux is formed, and a four-pole rotating magnetic field is formed. In this case, as a control winding 2-pole winding 14 is employed, the control field of likewise 2-pole are formed. In this power generation system, the switch 17 is provided, so that the two-pole winding is used as the main winding and the four-pole winding is used as the control winding as shown in FIG. As shown in (b), switching is possible between a case where a four-pole winding is used as a main winding and a two-pole winding is used as a control winding.
[0020]
Next, operation | movement of this electric power generation system is demonstrated with reference to FIG.1 and FIG.3. In this power generation system, the generator motor 11 is directly connected to the flywheel 16 as described above, kinetic energy is stored in the flywheel, and the generator motor is operated as a generator from the flywheel to extract the power energy. is there. Here, the generator motor 11 includes a two-pole winding and a four-pole winding, both of which can operate as a main winding and a control winding.
[0021]
First, as a pre-stage illustrated, drives the generator motor 11 as a motor flywheel 16 directly connected to the rotor 13 to reach a predetermined rotational speed S _0. At this time, the two-pole winding 14 is adopted as the main winding, and the four-pole winding 15 is adopted as the control winding at the same time, and the control current is supplied thereto, so that the rotor 13 is floated. That is, the generator motor 11 functions as a magnetic bearing, whereby the rotor 13 is levitated and supported without contact with the stator 12. This shifts to a state of functioning as a generator. Here, a large amount of kinetic energy is accumulated by rotating the rotating body having a large mass as the flywheel 16 at a high speed. The generated voltage at this time is V _0.
[0022]
When the load is generated at time t _1, the generator motor 11 is driven by a flywheel 16, and outputs the operation as a generator. Switching unit 17 is connected initially to adopt a 2-pole winding 14 as a main winding, the generated power generated in the main winding by the inverter device 19 to the power corresponding to the voltage and frequency of the commercial AC power source It is converted and supplied from the terminal 20 to the load side. On the other hand, a part of the generated AC power is introduced into the inverter device 22 and reversely converted into a current supplied to the control winding necessary for causing the generator motor 11 to function as a magnetic bearing and supplied to the control winding. The
[0023]
In a power generator that does not supply energy from the outside during power generation, such as a flywheel generator, the kinetic energy held by the load L decreases, and the rotational speed S decreases. The control device detects the rotational speed or the power generation voltage of the rotor, for example, when reduced to the switching voltage V ₁ which is set in advance, controls the two-pole windings which has been adopted as main windings ever winding Switching to use as a line, switching to adopt the 4-pole winding used as the control winding as the main winding (time t ₂ ). That is, in FIG. 1, the switch 17 is switched from the state indicated by the solid line to the state indicated by the dotted line.
[0024]
As a result of this switching, the main winding in which the generated voltage is generated as a generator is changed from 2 poles to 4 poles, and in the 4 pole winding, the electrical angle is as small as 1/2 with respect to the 2 pole winding. In this case, the voltage is doubled (from V ₁ to V ₀ ). Therefore, the generated voltage V can be returned to the initial voltage V ₀ by switching between the four-pole winding and the two-pole winding when the rotational speed S is reduced to about ½ of the original.
[0025]
Thereby, in the inverter device 19, the voltage supplied to the inverter unit is boosted by the DC / DC converter 19c, but the voltage itself supplied to the converter unit 19a becomes high, so the burden on the DC / DC converter 19c is reduced. can do. In other words, the kinetic energy stored in the flywheel is consumed, and even if the rotational speed is reduced to about half, it can be restored to the original generated voltage, thereby effectively using the energy stored in the flywheel. can do.
[0026]
In the above embodiment, an example in which kinetic energy accumulated in the flywheel is consumed and converted into generated power has been described, but various other applications are possible. For example, the electric energy stored in the storage battery is supplied to a generator motor having a two-pole winding and a four-pole winding to operate as a motor. Initially, the 4-pole winding is used as the main winding and the drive current is given. The 2-pole winding is given as the control winding and the rotor is levitated and supported as a magnetic bearing by static magnetic force. Do. The two-pole winding and the four-pole winding are each manufactured so that the rated operation as a motor can be performed independently, and the two-pole winding is manufactured to operate at a rated voltage lower than that of the four-pole winding. The electric energy stored in the storage battery is reduced by continuing the motor operation, and when the voltage drops, the four-pole winding that gives drive current is switched to the two-pole winding, and the control current is given 2 Switch the pole winding to the 4-pole winding. By this operation, it is possible to maintain a sufficient rated operation state with the two-pole winding as the main winding without increasing the voltage supplied to the electric motor. After switching, the 4-pole winding is used as the control winding, but the control winding current required for magnetic levitation is sufficiently smaller than the drive current of the main winding, so the required voltage is small, so the supply voltage Even if it falls, it will not interfere with the operation of the motor that is magnetically levitated. Further, since the two-pole winding after switching operates at a low rated voltage, the supply voltage to the inverter for adjusting the current applied to the two-pole winding can be operated at a sufficiently low voltage. Thus, by switching the windings employed as the main winding and the control winding, it is possible to return the power generation output or the motor output to the initial operation state.
[0027]
In the above embodiment, an example in which a quadrupole winding and a two-pole winding are provided has been described. However, in addition to this combination, if the number of poles is ± 2n (where n is an integer), the radius Directional static magnetic force is obtained. Therefore, as long as the above relationship of the number of poles is satisfied, it can be operated as a generator motor having the same magnetic bearing function as described above.
[0028]
Moreover, although the said embodiment demonstrated the example which switches a coil | winding in the state in which the generated voltage fell to the original 1/2, the winding ratio was adjusted beforehand, for example, the rotation speed fell to 2/3. Sometimes switching may be performed. Thus, various modified embodiments are possible without departing from the spirit of the present invention.
[0029]
【The invention's effect】
As described above, according to the present invention, the number of poles is different when converting mechanical energy into electric energy or converting electric energy into mechanical energy using a generator motor having a magnetic bearing function. By switching the role of the set of wirings, it is possible to return to the original generated voltage or rotational speed even when the supplied energy is reduced. As a result, the stored energy can be effectively used.
[Brief description of the drawings]
FIG. 1 is a diagram showing a power generation system according to an embodiment of the present invention.
FIG. 2 shows the current distribution of the magnetic bearing / generator in FIG. 1, where (a) shows an example in which a two-pole winding is used as the main winding and a four-pole winding is used as the control winding; ) Shows an example in which a 4-pole winding is used as the main winding and a 2-pole winding is used as the control winding.
FIG. 3 is a time chart showing an operation example of the power generation system shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Magnetic bearing combined generator motor 12 Stator 13 Rotor 14 Two pole winding 15 Four pole winding 16 Flywheel 17 Switch 18 Main inverter apparatus side 19 Main inverter apparatus 20 Terminal 21 Control inverter apparatus side 22 Control inverter apparatus

Claims (5)

Solid pole count 2n (where n is an integer) the stator and a only different first winding and the second winding, said first winding and a rotor with a current flows through the second winding In a magnetic bearing combined generator motor that floats and supports the stator,
Of the first and second windings, one winding is the main winding, the other winding is the control winding, and the generated power is connected to the main winding. An inverter device supplied to the inverter, an inverter device connected to a winding to be a control winding and supplying a control current to the winding;
A switch for switching one of the first winding and the second winding from the main winding to the control winding and the other winding from the control winding to the main winding is provided. Magnetic generator combined with generator motor. The generator motor according to claim 1, wherein the first winding and the second winding are a two-pole winding and a four-pole winding. When the generator motor is operated as a generator and the output voltage of the generator is reduced to a predetermined voltage, one of the first winding and the second winding is controlled from the main winding. the winding, magnetic bearings and generator motor according to claim 1, wherein the Turkey switched to the main winding and the other winding from the control winding.   4. The generator / motor combined with a magnetic bearing according to claim 3, wherein the output voltage of the generator rises to a predetermined magnification upon the switching. 5. The control device according to claim 3, wherein the switch includes a control device that adjusts a main winding current and a control winding current so as to maintain a state before switching at the time of switching. Magnetic bearing combined use generator motor.

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